On September 4th, 2023, a sample return canister will hopefully plummet through the skies of Utah. This sample return canister, after being charred due to the heat of atmospheric re-entry, will be brought to Johnston space center where scientists will open it to reveal up to 2 kilograms of the asteroid Bennu. This will mark the conclusion of an 8 year and almost 1 billion dollar mission called Osirus Rex.
Bennu
Bennu, the asteroid that Osirus Res is going to visit, is a Near-Earth Object (NEO), that was only discovered in 1999.
If we look at Bennu’s orbit from a top-view we can see that it intersects Earth’s orbit.
If we were to tilt our view, we would see that because of Bennu’s inclination, only one of these orbit crossing’s is close. Because this crossing is so close, and due to the relative locations of Earth in its orbit, Bennu is characterized as a potentially hazardous asteroid because it comes close to earth every 6 years.
Why do we want to go there?
Asteroids are the leftover building blocks of our solar system and understanding them is key in answering questions about the formation of our solar system. Due to Bennu coming so close to the Earth, sample return missions from Bennu are much easier to accomplish. Some of the most sensitive scientific instrumentation is either too sensitive to be launched on a rocket, or too large/heavy to fit on a spacecraft, so sample return missions allow us to study samples in a way that wouldn’t be possible using a spacecraft alone.
Particle Ejection
One really interesting part of Bennu is that it likes to throw rocks and other small debris into the region about it. Here’s a picture Osirus rex captured, note the particles to the lower left of Bennu.
Scientists are still studying the causes of this lofted material, but my personal pet theory (AKA Baseless Speculation) has to do with the Roch Lobe intersecting the surface of Bennu.
O-Rex
Osirus Rex, or O-Rex for sort, is the mission to visit Bennu, take a sample and return it safely to Earth.
What O-Rex has been up to so far
Since it’s arrival, O-Rex has been observing and measuring Bennu’s different properties. Once it mapped out the gravity field, it started slowly getting closer and closer to the asteroid trying to find the best place to take its sample. The search was narrowed down to four sites (Shown below), and finally, the nightingale site was chosen as the sampling target.
Sometime, most likely in July 2020, O-Rex will attempt a touch and go maneuver to acquire the samples from the nightingale site.
CAESAR…
One proposal for the next class of New Horizons missions was CAESAR, or as I call it Cold O-Rex. CAESAR was going to use a lot of technology from the O-Rex mission and conduct a sample return from a comet, instead of an asteroid.
…Struck down by DragonFly
CAESAR was one of two finalists for the next New Horizons mission but was beat out by DragonFly, a nuclear-powered octocopter the size of a small SUV, set to explore Saturn’s moon Titan in the mid 2030s
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